With the development of computer network and global mobile communications technologies, portable digital processing terminal devices have become a necessity in people's life and work, including laptops, Personal Digital Assistants (PDAs), computer peripherals, mobile telephones, pagers, household electronics, etc. They have strong processing capabilities and large storages, thereby forming a Personal Operating Space (POS). However, information exchange between these terminal devices mainly relies on cable connections, which is inconvenient to use. Thus, a wireless technology connecting the terminal devices in the POS and realizing movable and automated interconnection between the terminal devices, i.e., the wireless multi-hop network technology, is needed. In a wireless multi-hop network, communication data between non-neighboring terminal devices has to be transmitted with multi-hop routing.
There are four types of devices in a wireless multi-hop network: a terminal device, a routing coordinator, a network coordinator and a trusted center. The terminal device may communicate with other devices in the network, but can not transfer data for other devices in the network, i.e., the terminal device does not have routing function. Besides the functions of the terminal device, the routing coordinator is also responsible for transferring data for other devices in the network, i.e., the routing coordinator has the routing function. The network coordinator is responsible for transmitting network beacons, establishing a network, managing network nodes, storing network node information, searching for routing messages between a pair of nodes, and continually receiving information, and is also capable of transferring data for other devices in the network, i.e., the network coordinator has the routing function. Collectively, the network coordinator and routing coordinator may be referred to as coordinators. The trusted center is a key management center of the network, responsible for configuring key information for all the devices in the network. The network coordinator may function as the trusted center, or may designate other devices in the network as the trusted center. The wireless multi-hop network supports two types of network topologies: star topology, and point-to-point topology; and the point-to-point topology may further include mesh topology, and cluster topology, as shown in FIGS. 1 to 3.
For wireless multi-hop networks, existing key management methods normally include a pre-shared key-based key management method and a PKI-based key management method.
The first key management method is generally not suitable for large-scale networks, because it would be inconvenient to manage the pre-shared keys. The second key management method is not suitable for wireless multi-hop networks, because certificate management and the amount of communication are large.